Development of Methane Conversion Improvement Method by Recycling of Residual Methane for Steam Reforming. As a Part of R & D of HTGR-Hydrogen Production System.

The effects of reaction parameters, including reaction temperature and space velocity, on hydrogen production via steam reforming of methane (SRM) were investigated using lab- and bench-scale reactors to identify critical factors for the design of large-scale processes. Based on thermodynamic and kinetic data obtained using the lab-scale reactor, a series of SRM reactions were performed using a pelletized catalyst in the bench-scale reactor with a hydrogen production capacity of 10 L/min. Various temperature profiles were tested for the bench-scale reactor, which was surrounded by three successive cylindrical furnaces to simulate the actual SRM conditions. The temperature at the reactor bottom was crucial for determining the methane conversion and hydrogen production rates when a sufficiently high reaction temperature was maintained (>800 °C) to reach thermodynamic equilibrium at the gas-hourly space velocity of 2.0 L CH4/(h·gcat). However, if the temperature of one or more of the furnaces decreased below 700 °C, the reaction was not equilibrated at the given space velocity. The effectiveness factor (0.143) of the pelletized catalyst was calculated based on the deviation of methane conversion between the lab- and bench-scale reactions at various space velocities. Finally, an idling procedure was proposed so that catalytic activity was not affected by discontinuous operation.

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ICONE15-10825 DEVELOPMENT OF NUCLEAR HYDROGEN PRODUCTION SYSTEM BY DIMETHYL ETHER (DME) STEAM REFORMING AND RELATED TECHNOLOGIES

The Proceedings of the International Conference on Nuclear Engineering (ICONE) ◽

10.1299/jsmeicone.2007.15._icone1510_426 ◽

2007 ◽

Vol 2007.15 (0) ◽

pp. _ICONE1510-_ICONE1510

Author(s):

Kimichika Fukushima ◽

Hiroyuki Oota ◽

Kazuya Yamada ◽

Shinichi Makino ◽

Motoshige Yagyu ◽

...

Keyword(s):

Hydrogen Production ◽

Dimethyl Ether ◽

Steam Reforming ◽

Production System

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Decomposition of methane into carbon and hydrogen over Ni-Li/CaO catalysts

10.51415/10321/3056 ◽

2018 ◽

Author(s):

◽

Ronald Wafula Musamali

Keyword(s):

Fuel Cells ◽

Hydrogen Production ◽

Steam Reforming ◽

Methane Conversion ◽

Catalytic Decomposition ◽

Lithium Hydroxide ◽

Methane Decomposition ◽

Hydrogen Yield ◽

Carbon Fibres ◽

Decomposition Of Methane

Overdependence on fossil-based fuels and their effect on environment is a global concern by energy stake holders. Bulk of present day hydrogen comes from gasification of coal, steam reforming and partial oxidation of hydrocarbons. Steam reforming accounts for over 50% of world hydrogen production despite producing carbonaceous gases which are harmful to the environment and poisonous to both; proton exchange fuel cells and alkaline fuel cells. Natural gas is a preferred feed for hydrogen production, because it is abundantly available on earth. Catalytic decomposition of ammonia can produce clean hydrogen but ammonia itself is an air pollutant. Catalytic decomposition of methane into carbon and hydrogen is an attractive option to producing clean hydrogen because its products are carbon and hydrogen. In this work, five different catalysts comprising of varying quantities of nickel and lithium, supported on calcium oxide were synthesized by incipient wetness impregnation method and designated according to weight % as; 30%Ni/CaO, 37.5%Ni-12.5%Li/CaO, 25.0%Ni- 25.0%Li/CaO, 12.5%Ni-37.5%Li/CaO and 50%Li/CaO. The synthesized catalysts were characterized by (XRD, SEM, BET and TEM) and tested for methane decomposition. From the XRD patterns of the synthesized catalysts, distinct crystalline phases of CaO and NiO were positively identified in 50%Ni/CaO according to their reference JCPDS files. Introduction of Lithium hydroxides improved the crystalline structure of the Ni/CaO catalyst. SEM analyses of the catalyst material using Image-J software confirmed that all catalyst materials were nanoparticles ranging from 3.09-6.56nm. BET results confirmed that, all the catalysts are mesoporous with pore sizes ranging from 20.1nm to 45.3nm. Introduction of LiOH to Ni/CaO generates mesoporous structures by destructing the lattices of the CaO structure during the formation of Ni-Li/CaO species. Particle size distribution in TEM analyses revealed that, a higher nickel loading in the catalyst favours the formation of carbon nanotubes while higher lithium hydroxide loading favours the formation of carbon fibres (CF). Low yield of carbon fibres from methane decomposition on unsupported Ni catalyst in 50%Ni/CaO was attributed to the presence of large Ni particles with low index planes which were incapable of dissociating the unreactive methane molecule. The aim of this work was to synthesize a catalyst for use in decomposition of methane into carbon and hydrogen, that addresses drawbacks of traditional solid metal catalysts such as sintering and coking. From the experimental results, 37.5%Ni-12.5%Li/CaO catalyst recorded 65.7% methane conversion and 38.3%hydrogen yield while 50%Ni/CaO recorded the lowest methane conversion of 60.2% and a hydrogen yield of 35.7% at 650℃. Outstanding performance of the 37.5%Ni-12.5%Li/CaO catalyst is attributed to the incorporation of lithium hydroxide which provided more catalyst active sites and a molten environment for proper dispersion of the nickel metal. The solid 50%Ni/CaO catalyst readily deactivated due to coking unlike the supported molten 37.5%Ni-12.5%Li/CaO catalyst in which methane decomposition reaction took place by both surface reaction and chemisorption.

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Hydrogen Production From Methane Steam Reforming With CO2 Capture Through Metallic Membranes

Volume 6A: Energy ◽

10.1115/imece2016-65363 ◽

2016 ◽

Cited By ~ 1

Author(s):

Roberto Carapellucci ◽

Eric Favre ◽

Lorena Giordano ◽

Denis Roizard

Keyword(s):

Hydrogen Production ◽

Gas Turbine ◽

Steam Reforming ◽

Production System ◽

Membrane Separation ◽

Waste Heat ◽

Methane Steam Reforming ◽

Small Scale ◽

Separation Unit ◽

Syngas Production

As an energy carrier, hydrogen has the potential to boost the transition toward a cleaner and sustainable energy infrastructure. In this context, steam methane reforming coupled with carbon capture through membrane separation is emerging as a potential route for hydrogen generation with a reduced carbon footprint. A potential way to improve the efficiency and reduce costs of the entire process is to integrate the hydrogen production system with a gas turbine power plant, using a fraction of waste heat exhausted to provide the heat and the steam required by the endothermic reforming reaction. The paper assesses the techno-economic performances of a small-scale hydrogen and electricity co-production system, integrating a syngas production section, a gas turbine and a membrane separation unit. The simulation study investigates two main configurations, depending on whether the gas turbine is fed by hydrogen or natural gas. For each configuration, energy and economic performance indices are evaluated varying the main plant operating parameters, i.e. the steam reforming temperature, the permeate sweep dilution, the membrane pressure ratio and the technology of gas turbine.

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Transport Mechanism of Methane Steam Reforming on Fixed Bed Catalyst Heated by High Temperature Helium for Hydrogen Production: A CFD Investigation

Volume 3: Nuclear Fuel and Material, Reactor Physics and Transport Theory; Innovative Nuclear Power Plant Design and New Technology Application ◽

10.1115/icone25-67641 ◽

2017 ◽

Author(s):

Feng Wang ◽

Jing Zhou ◽

Qiang Wen

Keyword(s):

High Temperature ◽

Hydrogen Production ◽

Production Rate ◽

Steam Reforming ◽

Methane Conversion ◽

Methane Steam Reforming ◽

Inlet Temperature ◽

Hydrogen Production Rate ◽

Inlet Velocity ◽

Methane Steam

Performance of methane steam reforming reactor heated by helium for hydrogen production has been studied by numerical method. Results show with the increasing of reactant gas inlet velocity, temperature in the reactor drops, leading to the decreasing of methane conversion and hydrogen production rate. Methane conversion, hydrogen production and hydrogen production rate rise with the increasing of reactant gas inlet temperature, while the increasing degree of system thermal efficiency reduces. Besides, with helium inlet velocity rising, temperature in the reactor increases and reaction in the reactor becomes more sufficient. Therefore, methane conversion and hydrogen production also increase when helium inlet temperature of rises, but its influence is weaker compared to that of helium inlet velocity. In the process of methane steam reforming heated by high temperature gas cooled reactor (HTGR) for hydrogen production, lower reactant gas inlet velocity, suitable inlet temperature, higher inlet velocity and higher HTGR outlet temperature of helium are preferable.

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Sensitivity analysis and optimization of a membrane reactor for hydrogen production through methane steam reforming

Revista Mundi Engenharia Tecnologia e Gestão (ISSN 2525-4782) ◽

10.21575/25254782rmetg2020vol5n61315 ◽

2020 ◽

Vol 5 (6) ◽

Author(s):

Igor Nardi Caxiano ◽

Lizandro De Sousa Santos ◽

Diego Martinez Prata

Keyword(s):

Hydrogen Production ◽

Steam Reforming ◽

Methane Conversion ◽

Membrane Reactor ◽

Packed Bed ◽

Operating Conditions ◽

Methane Steam Reforming ◽

Maximum Efficiency ◽

Promising Alternative ◽

Methane Steam

Hydrogen is one of most studied sources for clean power generation in the near future. Nowadays, hydrogen is mainly produced through methane steam reforming in packed bed reactors, with a promising alternative to this technology being the implementation of hydrogen-selective membrane reactors. This work compares the isothermal mathematical models of both designs by assessing the effects of multiple design variables on methane conversion, while also providing recommended operating conditions for maximum efficiency of the membrane reactor over the packed bed technology. Additionally, an optimization study is carried by dividing the reactor length in isothermal segments to achieve higher efficiency. Results showed that the membrane technology considerably increases hydrogen production, with temperature being the most influential variable on methane conversion. While the temperature profile optimization provided similar conversions compared to the isothermal models, the membrane reactor’s efficiency was increased, further justifying its implementation.

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Hydrogen Production via Steam Reforming: A Critical Analysis of MR and RMM Technologies

Membranes ◽

10.3390/membranes10010010 ◽

2020 ◽

Vol 10 (1) ◽

pp. 10 ◽

Cited By ~ 2

Author(s):

Giovanni Franchi ◽

Mauro Capocelli ◽

Marcello De Falco ◽

Vincenzo Piemonte ◽

Diego Barba

Keyword(s):

Hydrogen Production ◽

Steam Reforming ◽

Research Group ◽

Methane Conversion ◽

Fossil Fuels ◽

Membrane Separation ◽

Hydrogen Permeation ◽

Experimental Tests ◽

Pressure Profile ◽

Small Scale

‘Hydrogen as the energy carrier of the future’ has been a topic discussed for decades and is today the subject of a new revival, especially driven by the investments in renewable electricity and the technological efforts done by high-developed industrial powers, such as Northern Europe and Japan. Although hydrogen production from renewable resources is still limited to small scale, local solutions, and R&D projects; steam reforming (SR) of natural gas at industrial scale is the cheapest and most used technology and generates around 8 kg CO2 per kg H2. This paper is focused on the process optimization and decarbonization of H2 production from fossil fuels to promote more efficient approaches based on membrane separation. In this work, two emerging configurations have been compared from the numerical point of view: the membrane reactor (MR) and the reformer and membrane module (RMM), proposed and tested by this research group. The rate of hydrogen production by SR has been calculated according to other literature works, a one-dimensional model has been developed for mass, heat, and momentum balances. For the membrane modules, the rate of hydrogen permeation has been estimated according to mass transfer correlation previously reported by this research group and based on previous experimental tests carried on in the first RMM Pilot Plant. The methane conversion, carbon dioxide yield, temperature, and pressure profile are compared for each configuration: SR, MR, and RMM. By decoupling the reaction and separation section, such as in the RMM, the overall methane conversion can be increased of about 30% improving the efficiency of the system.

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Hydrogen Production by Methane Steam Reforming Over Ru and Cu Supported on Hydrotalcite Precursors

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.324.453 ◽

2011 ◽

Vol 324 ◽

pp. 453-456 ◽

Cited By ~ 6

Author(s):

Doris Homsi ◽

Samer Aouad ◽

Cedric Gennequin ◽

Antoine Aboukaïs ◽

Edmond Abi-Aad

Keyword(s):

Hydrogen Production ◽

Cobalt Oxide ◽

Steam Reforming ◽

Methane Conversion ◽

Nitrate Solution ◽

Methane Steam Reforming ◽

Cobalt Oxides ◽

X Ray Diffraction ◽

X Ray ◽

Methane Steam

Co6Al2oxide was prepared using the hydrotalcite route. The obtained solid was thermally stabilized at 500°C and then impregnated with 5 wt.% copper or 1 wt.% ruthenium nitrate solution followed by calcination at 500°C under an air flow. X-ray diffraction results showed that the calcination of the impregnated solids led to the formation of various oxides (CuO, RuO2, Co3O4, CoAl2O4, CoAl2O4). The different impregnated and non impregnated solids were tested in the methane steam reforming reaction (MSR). Methane conversion did not exceed 5% at 800°C in the case of the non impregnated solid, whereas the impregnation strongly enhanced the reactivity: ~89% and ~92% conversions were reached at 600°C for Cu and Ru respectively. The good reactivity of ruthenium impregnated catalyst was attributed to the formation of easily reducible ruthenium and cobalt oxide species at the surface of the support. The addition of ruthenium made the reduction of surface and bulk cobalt oxides possible at lower temperatures.

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